Thursday, February 21, 2008

Negative One Equals One

My friend showed this to me a few days ago...

-1 = -1
-1/1 = 1/-1
sqrt(-1/1) = sqrt(1/-1)
sqrt(-1)/sqrt(1) = sqrt(1)/sqrt(-1)
sqrt(-1)*sqrt(-1) = sqrt(1)*sqrt(1)
-1 = 1

In case you are wondering, there is in fact an error in the proof. The operation done between the third and fourth lines is not possible.

4 comments:

Tom said...

Logic proof that Ray Charles is God (with one fallacy).

God is love.
Love is blind.
Ray Charles is blind.
Ray Charles is God.

Stephanie said...

Anthony, this makes absolutely no sense to me. You are a geek. Bless your heart.

Ryan said...

Actually, the error isn't in the third line. That's a completely plausible assumption:

(a/b)^(x) = (a^x)/(b^x)

where a=1 and b=-1 and x=(1/2) (a and b vice versa'd on the other side of the equation)

Which means the fourth line can be rewritten as:

i/1 = 1/i

i*i=1*1
bringing us th final conclusion of:
-1 = 1

Where the math calls apart is assuming that sqrt(1) = 1

It actually equals plus or minus 1.

And seeing as the only answer where the square of i and the square root of 1 coincide is at -1 we see that the math actually falls apart for a different reason.

Continental Drift said...

Here's another one:
in Electrical Engineering the imaginary number j = sqrt(-1)
j^2 = -1 then j^2 * j^2 = -1 * -1 = 1 right?
But:
1 = sqrt (j^2 * j^2)
1 = sqrt (j^4)
1 = j^2
1 = -1

what went wrong?